Ex vivo gene therapy in autologous bone marrow stromal stem cells for tissue-engineered craniomaxillofacial bone regeneration

In therapeutic bone repairs, autologous bone grafts conventional or vascularized, allografts, and biocompatible artificial bone substitutes all have their shortcomings. The bone formed from peptides (rhBMPs), demineralized bone powder or combinations of both is small in size. The tissue engineering may be an alternative for cranial bone repair. We develop animal models to test the hypothesis that ex vivo replication defective Adenovirus mediated human BMP-2 gene transfer to bone marrow mesenchymal stem cells (MSCs) enhances the autologous bone formation for repairing a critical size craniomaxillofacial defect. The MSC was implanted by using ex vivo adenovirus BMP-2 medicated gene transfer to the expanded MSC 7 days before implantation with a concentration was 5x10⁷/ml of collagen type I, and the control site using adenovirus β-galactosidase under the same condition. The BMP-2 cell/construct site showed complete whitish solid bone formation after 3 months and the HE and Von Kossa stains demonstrated that mature woven bone with well mineralization. 3D CT image showed a wholesome repair in both cranium and maxilla. Quantitative analysis demonstrated that there was significant different (p<0.001) in bone formation. The biomechanic test did reveal no significant statistical difference in the stiffness of new bone formed by BMP-2 cell construct and the normal maxilla bone. The data evidenced de novo bone formation with quality as good as normal craniofacial bone, and thus capable of sustaining gravity load. The results demonstrated that ex vivo gene therapy by adenovirus BMP-2 transduction will induce and enhance craniomaxillofacial bone regeneration.